2. Templates

This node describes the syntax and semantics of templates defined by
tempo-define-template. The first part deals with the syntax of
the function itself, while the second part describes the different
template elements.

2.1 Template syntax

This function creates a template and binds it to a new variable named
tempo-template-name. It also creates a new command under
the same name. This command expands the template at the current point,
when invoked.

The parameter elements is a list of template elements. The
possible elements are described in 2.2 Template elements.

If a tag is supplied, it must be a string which is placed in
taglist or tempo-tags. This string is used for automatic
completion. When tempo-complete-tag is called and tag is
matched, the template template defined with tag is
inserted. (see section 1.3 Tag lists and automatic completion for more information on tags and tag
lists)

2.2 Template elements

These are the predefined elements you can use in a template definition:

STRING

A string in a template is first run through the string preprocessors in
tempo-insert-string-functions and the result is inserted.

p

This denotes an "interesting" position in the template. When the
template is expanded, this position is remembered with a mark on the
tempo-marks list. See section 4. The mark list.

r

This works in a similar way to the above p element, but if the
template command is given a prefix command, the current region is placed
here. This means that the preceding part of the template is expanded
before the region, and the rest is expanded after. There can be only one
r in a template. If transient-mark-mode is active
(see section `The Mark and the Region' in the GNU Emacs Manual) the current region is used and the prefix argument is ignored.

If the variable tempo-insert-region is non-nil, the behaviour of
the r element is reversed.

(p prompt [name [noinsert]])

(P prompt [name [noinsert]])

(r prompt [name [noinsert]])

If the variable tempo-interactive is nil, the elements (p
...)) and (P ...) work exactly like a single p,
and (r ...) works like a single r.

But, if you set tempo-interactive to t the user is
prompted for a string to insert when the template is expanded. The
prompt is taken from the prompt parameter. The element (P
...) works like (p ...) with the exception that
tempo-interactive is forced to t, which means that the
user will always (almost always, see below) be prompted.

If you provide a name to any of these, and interactive prompting
is taking place, the resulting string is saved in a local list so it can
be inserted again later with the (s ...) element. See section 5. The save list, for more detailed information.

As a special case, if the save list already contains something under
name, it is used directly, and no prompting is done, even with a
(P ...) element.

The third argument, noinsert, disables insertion of text. If
tempo-interactive it non-nil, and a name has been
provided, normally a string is read through the minibuffer and then
inserted and saved. When noinsert is non-nil, nothing is
inserted, and the text is only saved for later.

Stylistic conventions (invented by me) dictates that these elements
should be placed as early as possible in template definitions.

r>

This element works like r, but it also indents the region it is
expanded around.

(s name)

This looks up name in the save list and inserts what it
finds. Note that if it finds a string, it is not run through the string
preprocessors.

&

An ampersand inserts a newline if there are characters other than
whitespace before the current point on the line. Otherwise it does
nothing. This means that it makes sure that the following text always
starts a new line, possibly with some leading whitespace.

%

A percent sign inserts a newline it there are characters other than
whitespace after the current point on the line. Otherwise it does
nothing.

n

Simply inserts a newline character.

>

This does not insert any text. Instead it indents the line according to
the major mode, by calling indent-according-to-mode. Note that in
order to get best results, you often should place this after the text
you want to place on the line, as this could affect the indentation.

n>

Inserts a newline and indents line. It is the same as a n
followed by a >.

o

Works like %, but leaves the point on the first line. Note that
this can cause great confusion if you are not careful. If the o
is the first element in a template which is inserted at the beginning of
a line, strange things happen. This is due to odd behaviour in
open-line.

nil

A nil element is simply igonred. That means that a lisp
expression (see below) that returns nil does not insert anything.

(l element1element2...)

This element is most useful as a return value from a lisp expression
(see below). It inserts the elements using the same rules as all
template elements.

Anything else

All unrecognized elements are checked to see if it is a user-defined
elemet. See section 2.3 Defining your own elements. If isn't, it is assumed to be
a lisp expression and is evaluated in a normal fashion. The result from
such an expression is taken as a template element an is inserted
according to the usual rules. If you don't want to insert anything, make
your expression return nil. If you want to insert more than one
element, use the (l element1element2...)
element.

2.3 Defining your own elements

The variable tempo-user-elements contains a list of functions to
call when an unrecognized element is found.

Variable:tempo-user-elements

A list of functions. When tempo-insert is called with an element
it doesn't recognize, it checks this list by calling each function with
the element as the single argument. A function in this list should take
a single element as argument and return nil for elements it
doesn't recognize. If it does recognize an element, it should return
another element to be inserted, e.g. a string. If the function wants to
return an authorative nil, it could return either "" or
(l).

Do not use any one-charachter tags for your own elements. These are
reserved for future tempo enhancements.